This application seeks funds for the purchase of two mass spectrometers to comprise a departmental facility: (1) a Finnegan LCQ Benchtop MS System with electrospray and chemical ionization capability, associated gradient LC pump system, positive- and negative-ion detection, mass/charge range of 50-2000 daltons; and (2) a Finnegan MAT Model SSQ 7000 MS/DS mass spectrometer with electron impact, chemical ionization, and fast atom bombardment capability, positive- and negative-ion detection, and mass/charge range to 2500 daltons. Both systems include powerful and versatile bundled computer systems for instrument control and data manipulation. The proposed equipment is designed to replace the single outdated departmental instrument, which can no longer be brought to adequate levels of performance. The acquisition of reliable mass spectral data is vital to the activities of all of the research groups in the department that engage in chemical and biochemical synthesis. The current lack of this capability is a major impediment to the progress of a variety of NIH- funded programs as well as projects supported by other agencies. The requested instruments are modern "workhorse" machines that have important capabilities previously unavailable to departmental users. The instruments are designed to accomodate the two major types of samples generated by our research groups: standard solid and liquid small-molecule samples, including organic, inorganic, and organometallic compounds, will be served by the SSQ-7000, whereas biological molecules, biopolymers and other large and small polarizable structures will be routinely analyzed with the LCQ electrospray instrumentation. Given the vary active nature of the department's synthetic efforts concerning both types of molecules, the user base for the two instruments will be large.